The biggest issues people think about marrying-or-not (especially, when talking about teens), are
Marriage is not worse than anything else, in any of the categories. (That is why I find that especially unfair that, marriage is the forbidden.) But, people need to keep in mind that, marrying needs thinking. Otherwise, one might mess up in all of the categories, within marriage, too.
Ironically, the good old style (when there was no "welfare state"), welfare was with family networking (big families). Youngsters would first start their families, while living with their (parental) families. In time, the grannies would keep there. The good old style of welfare.
The irony is that, now USA is thinking what to do with baby-boomers retiring.
Two who find living as singles possible, most likely would find living as a couple, no more costly.
Exceptions may be singles who live in dormitories, or non-personal rooms at home.
But if thinking of such cases, why not just relax what you expect of such a married couple's "necessary" (permanent) dwelling resources, too?
The Quran, Nur(24):32, is endorsing marriage, such that, if the couple had poverty, Allah helps.
A hadith informs that, all babies are born with their food/accommodations (but does not inform about whether they are born with sufficient money for all the excesses that our "modern societies" try to stick on us, through suggestiveness of imitating Joneses, or because our state-rulers think we should waste our time & resources through sth).
The next, Nur(24):33, cautions those who may not be capable of marrying, to keep their chastity, and that, Allah may, in the future, change that (whatever is the trouble, maybe unavailability of appropriate spouse-nominees, or the worldly situation is making marriage impossible (or, risky)). Some exegetes may be interpreting Nur(24):33 w.r.t. finances, too, but Nur(24):32 does seem to rule-out that concern, I think (but depends on how far you constrain yourself to have various worldly "needs" at the start of your marriage, or how "in guarantee," without daily concerns of living, food).
If sex is not criminal out-of-wedlock, then how is marrying unlawful?
Worse, lots of states (in USA), allow marrying young, if there had been sex. That is no way of promoting a chaste style of marrying. Worse, lots of incidences of fooling a girl to have sex with her out-of-wedlock, with (supposedly) planning to marry her in the future, had been in court cases.
The cases I know were in T.C. cases. I have no opinion whether there had been any such cases in USA (or, a lot). But now, U.S. laws, if they make that the exclusive option (unless the girl would wait until the relatively old age), the potential is obvious.
Pedophilia is a trouble. But parents and courts weigh who is sufficiently mature for marrying.
Ironically, if you list post-pubescents as "child" ("pedo"), and you forbid marrying, while youngsters turn out to have sex, then pedophiles might truly have their niche, there.
Ironically, in USA, both of the extremes (promoting condoms, or abstinence) have supporters, while the option in the middle, that is, marrying, is unlawful, until "sufficiently old to think."
Worse, how I understand, as time goes by, lots of youngsters are not about getting a lot more wisdom toward marrying, but the vice versa. What they get experience in, is how the opposite-sex works (plural, statistics). They know (having experience) how to get in and out of relationships, with a herd of lovers (hopefully, serial-monogamy, but perhaps worse). None of that is anything to educate you about a (stable) marriage.
A teen's brain is found to be still developing -- a period that is well-known to have opposite-sex, and social, interests. Presumably, if he/she has a spouse, developing specific to his/her spouse.
Ironically, marriage-opposers try to interpret that (teen brain) developmental status, not to allow people to start family-making (with deep bonding), but vice versa, to keep out of marriage, but letting "popular sports" such as teen-flirting & sex-out-of-wedlock.
Malthus would not love population-explosions, but Muhammed (s.a.s.) might (if you would raise your children well). With a family, children have their parents, and if big family, their grannies, too.
Two grannies are better than one (when one is not available, if the other may help).
But if families are portable, then one set of parents may remain remote (then, the couple may share their times with either family). But that concern, may apply mostly in cases of just-starting-a-big-family, not in the case of having a truly big family (aunts, uncles), with a well-known history there (because one couple of parents may relocate for business, but the rest of the family still remain there, for conveniently sticking with).
Without marrying, that "divorce" is the normalcy (instantly, or following the dating times). If some of who marry, might split, that is not marvelous, although not falling behind any alternative, either.
The trouble (mainly with blacks of USA), is MFS (the "missing father syndrome"). Not necessarily not knowing who he was, but simply not having him around, any more. (That was a problem known in 1990s, news articles. There seems no hint to believe that statistics getting better, yet.) Thus, there was a long-known culture. Work against.
Ironically, unfortunately, now that I suggest to all people that, marriage is a better option than out-of-wedlock sex, if people who would not normally marry, might marry, they might (maybe) think casually to divorce, too. Impulse marriages are understood to be relatively more likely result in divorce. Therefore, I need to warn that, you have to neglect the divorce statistics (if they are high). Your marriage is your ship. Keep yours, well. There is no sense of fashion, to sink your ship "because" others seem to sink.
The families in old times, had less outside sources to mess with their private time.
Now, people watch TV more than talking with their families. While TVs bombard your family, you need to keep attentive, too. Camaraderie with your spouse, to sift the influences, for tailoring to yourselves, would be valuable. Otherwise, if you would become strangers, and in time, get lost in the normalcy of divorce (by statistics), then that is not necessarily about marrying at young age, but probably the vice versa.
Marrying relatively quickly, is not the quickest. 15 or more, is not necessarily a fresh mind/spirit.
Fine-tuning might start at puberty (or, before). Personalities accumulate.
Thus, allocating makes sense. Sex is not the cause. Personalizing, fine-tuning is.
Most likely, few or none of the [young] couples in USA, live with Islamic style. Probably none is adopting the Islamic hijab (tesettur) style of modesty. The "openness" might risk the family, too.
The rules of Islam, are optimal for facilitating families. Therefore, valuable for non-muslims, too. Non-muslims might reflect how closely they fit to the Islamic standards.
For your own case, you might think you have some good alternative to replace some portion of what Islam lists (as commands for muslims) -- but chances are, that is risky.
In the worst case, you might need to fend off satanical assaults, too.
For fending off potential risks of committing sin (and not to cause other people doubt about you, either), Islam suggests to not stay behind walls (or, invisible in remote places) with opposite-sex, other than those from your own family. Such cautions may block out lots of satanical attempts, before they may find a chance to start. That is helpful for keeping other people' minds (& lives) free from dirt, too, because they will not see you as (bad) examples of hiding in private (with guessable sins), with others.
Probably all of us would acknowledge that, marrying is a safeguard against sexually-transmitted illnesses. But people who live promiscuously, might contract the illness to their spouses.
There, Islam is again good for keeping well. The Quran is not allowing adulterers (who have out-of-wedlock sex) to marry non-adulterers. (Some seem to neglect that.)
The couple might need to know the medical success estimate of a prospective pregnancy/labor.
Critiques list potential labor-time trouble (then, obstetric-fistulas), as likely, in the case of too-young (too-small-physique) women. But that again, is not a point against marriage. Vice versa. The father of the girl might think that, and postpone (by vetoing) the marriage. (But as in the case of category-crossers, people might be neglectful.)
Perhaps, they would think the couple to marry and have sex, but not pregnancy. (Contraceptives.) Or the couple might think having their first baby with cesarean--section (think well, though, because that might not let having lots of babies, afterward).
Out-of-wedlock people would hope only the contraceptives to work (and that is available in marriage, too). Or, if something goes wrong (torn-condom, or null-drug), then they might fall-back to abortions, or, having the baby. Nothing above marriage.
By the way, I guess that a theory of "old-wives" may be correct. That is, having lots of sugar in pregnancy, may boost the birth-weight of the baby -- and that excess is what you would not wish.
If sugar is the most affordable (for poor families), then feed her before pregnancy. That is relatively safe, because sugar becomes fat (in body), within a week. But, sugar is not nutricious. If affordable, try following good-diet habits (for both feeding her, & while fetus develops in womb), and mind about pregnant woman's appetite signals, too.
By the way, I am not a medical researcher, nor doctor. (I reserve the right to experiment in the future, though.) The theory I endorse, is because just within (or, around) the week of having found the obstetric-fistula information (in 2009), I saw a few (news and biological-journal) articles that were talking about cancer-stem-cell-hypothesis. Because both fetus and cancer may be stem-cells, and both thriving on sugar, I thought that the said "old-wives" theory may be correct. But this has to be tested. Otherwise, I would/will be sorry if some follow my advice but then, for example, if fatty-mothers (not sugar, but mother's fatness) would turn out to cause fat babies.
Having a family, is hardly a true cause not to achieve.
Within a big family, that actually would work in the routines of the establishment, too.
Grannies nurturing the kids, while teens go highschool, then university, then work.
That works for lots of people.
Furthermore, I might list a few of what I favor, too.
Formazing is a flexible style for life-long self-development.
No need to "go to work" 9-to-5. If you would like to achieve, then you might work at home, too.
Mothers have had lots of homely crafts, throughout history.
Internet is working well, for lots of people, to work remotely, with people from around-the-world. Your past work/projects (results), may remain on your public records -- or, your internet sites. (If people request your CurriculumVitae, the records are there.)
So far, I have not seen the optimal sort of records facilities, around (for reporting all past projects of people, publicly). But that is not hard to start, or distribute. Just publicly-keeping, archiving the results, is sufficient, for most.
The Islamic holy book, the Quran, in Nisa(4):5-6, lists rules for not wasting resources & humans.
For mentors/guards of orphans -- or, for all, if parents (or, olders for selves) mind how.
If a person is able for work, and has resources (available from his/her family, or at no extra (usury/interest) cost but only with know-how of project-making or investing), then he/she may get/find his/her money for that work.
"Financial-independence" is not necessary for marrying, and may start (if ever) before or after marital age -- depending on the context and the work-abilities of a person.
Ironically, the "modern-society" is full of people with jobs (or, diplomas) that have little or no worth in itself, but fits to a context (or, employer-whim in setting hiring-priorities). Furthermore, family businesses (throughout history) have been harbor for the family (not individuals, but all), and then, "independence from family" is presumably most often not a goal, at all.